The present invention relates to a broadband communication device. More particularly, the present invention provides a Si-waveguide-based broadband polarization splitter-rotator with low loss and high extinction ratio for polarization-independent silicon photonics communication systems.
Over the last few decades, the use of broadband communication networks exploded. In the early days Internet, popular applications were limited to emails, bulletin board, and mostly informational and text-based web page surfing, and the amount of data transferred was usually relatively small. Today, Internet and mobile applications demand a huge amount of bandwidth for transferring photo, video, music, and other multimedia files. For example, a social network like Facebook processes more than 500 TB of data daily. With such high demands on data and data transfer, existing data communication systems need to be improved to address these needs.
Silicon photonics has become very popular for these applications because of the potential to combine high performance with low-cost fabrication. In addition, polarization multiplexing is another attractive, low-cost, and simple way to increase transmission capacity. Polarization splitter-rotator (PSR) is a key element for polarization management in next generation polarization-independent silicon photonics circuits. A polarization splitter-rotator preferred for photonic integrated circuits (PICs) should simultaneously have features like compact size, high extinction ratio, low insertion loss, broadband range, stability, simple structure and high tolerances in manufacture. Conventional polarization splitter-rotator is either wavelength sensitive (not suit for broadband operation) or based on prism (hard to be made in super compact size).
Therefore, it is desired to develop improved compact polarization splitter-rotator that is low insertion loss and wavelength insensitive across entire C-band or O-band window for the integrated silicon photonics circuits.